1. Field of the Invention
The present invention relates to a recording/playback apparatus for writing or reading continuous data in/from a magnetic disk device which is included in electronic equipment for handling continuous data such as audio and video data, and more particularly, to a recording/playback apparatus which satisfies a device performance that is desired by the operator without interrupting continuous data.
2. Description of the Related Art
A conventional recording/playback apparatus has been provided for recording or reproducing continuous data which have been obtained by digitizing analog data of video or the like by the apparatus itself or which have originally been digital data. The conventional recording/playback apparatus has a recording device using a disk type recording medium, which is a so-called hard disk drive, as a recording/playback means, and an upper control unit for controlling the continuous data and also for integrally controlling data input/output or the like. FIG. 14 is a block diagram illustrating the construction of the main parts of the conventional recording/playback apparatus.
In FIG. 14, numeral 1 denotes a disk type recording medium, and numeral 3 denotes a motor for rotating the disk type recording medium 1. Further, numeral 2 denotes a recording/playback head for writing digital data that are transmitted from a lower control unit 5 in the disk type recording medium 1, or for reading the digital data that are written in the disk type recording medium 1 and transmitting the data to the lower control unit 5. Further, numeral 4 denotes an actuator which enables a seek operation for moving the recording/playback head 2 on the disk type recording medium 1 in the direction of the radius of the medium 1, and numeral 6 denotes a memory for temporarily holding the data when the data are written in or read from the disk type recording medium 1 or when an error correction process or the like is carried out. Numeral 7 denotes an interface unit for exchanging data and commands with an upper control unit 9. Numeral 5 denotes a lower control unit for controlling the interface unit 7, the memory 6, the actuator 4, the motor 3, and the recording/playback head 2. An apparatus comprising the above-described constituents 1 to 7 is considered as a single device which is known as a hard disk drive, and such a hard disk drive is regarded as a disk device 13.
Further, numeral 12 denotes an input unit for receiving an input of data such as video data, and numeral 11 denotes an output unit for outputting the data to a video display unit such as a monitor. Numeral 8 denotes an interface unit for exchanging data and commands with the disk device 13. The interface unit 8 transmits a command or data to be written to the disk device 13 by a command 14, and the interface unit 8 receives a response or read data from the disk device 13 by a response 15 to the command 14. Numeral 10 denotes a memory for temporarily holding the continuous data such as video data which are supplied from the input unit 12, for temporarily holding the data before being outputted to the output unit 11, or for temporarily holding the data for processing the data, performing an error correction process or the like on the data. Numeral 9 denotes an upper control unit for integrally controlling the processes such as data reading, writing and the like through the input unit 12, the output unit 11, the memory 10 the interface unit 8, and the disk device 13.
The disk device 13 is considered to be a sort of hard disk drive as a recording unit of a computer. In the conventional recording/playback apparatus, a command to be transmitted by the command 14 is a single command, and the response 15 to the command 14 is also a single response.
Next, the operation of the conventional recording/playback apparatus will be described according to a flowchart shown in FIG. 15. FIG. 15 is a flowchart illustrating the operation of the conventional recording/playback apparatus.
Initially, in step S101, the upper control unit 9 sends a single command 14 to the disk device 13.
For example, it is assumed that the command 14 is a command for reading a predetermined quantity of data from an address A on the disk type recording medium 1.
The disk device 13, which has received the command 14 in step S102, controls the actuator 4 by the lower control means 5 in step S103, and moves the recording/playback head 2 to the address A on the disk type recording medium 1. Then, in step S104, it is determined whether a servo is operated or not. When no servo is operated, the disk device 13 returns to an operation for operating the servo. When the servo is operated, the disk device proceeds to step S105. In step S105, the disk device 13 executes reading of data from the disk type recording medium 1, and confirms the reading operation in step S106. When the reading operation is xe2x80x9cOKxe2x80x9d, the disk device 13 proceeds to step S108; otherwise, the disk device proceeds to step S107. In step S107, it is determined whether the reading operation exceeds a limited number of times that is previously set. When the reading operation is under the limited number of times, the disk device 13 returns to step S104 to perform the reading operation again. When the reading operation reaches the limited number of times, the disk device 13 proceeds to step S110.
In step S108, the lower control unit 5 sends the data which is read in step S105 to the upper control unit 9 through the interface units 7 and 8, and the upper control unit 9 receives the data. When the data transmission to the upper control unit 9 is completed, the disk device 13 proceeds to step S110, and sends a response 15 to the upper control unit 9 as to whether the process indicated by the command 14 is completed or not.
When the disk device 13, which is provided with the disk type recording medium 1 and which operates as described above, is used as a recording unit of a computer, the disk rotation speed and the seek speed for moving the recording/playback head 2 are usually set at high speeds for the speed-up of data processing. However, such speed-up causes a drawback in that noise is high and power consumption is also high as a device. As a method for solving this drawback, Japanese Published Patent Application No. Hei. 7-334950 discloses a disk device in which the user can select a mode for reducing the disk rotation speed or the seek speed at the sacrifice of the data processing speed.
In the device disclosed in Japanese Published Patent Application No. Hei. 7-334950, however, when a high rotation speed is selected, stillness and power consumption are sacrificed although high-speed data processing can be achieved. On the other hand, when a low rotation speed is selected, high-speed data processing cannot be achieved although stillness and power consumption are satisfactory.
The reason the above-described operations is as follows. The conventional disk device 13 has been known as a recording unit of a computer and is only required to perform reliable recording and playback of data even when the data are discontinuous on the time axis. Therefore, the stated requirement is satisfied as long as the user can selectively specify a performance on which the user places a great importance as described above.
When the recording/playback apparatus that is provided with the disk device 13 handles video or audio data, it is required, however, that the upper control unit 9 performs processes such as writing/reading of continuous-data on the time axis such as video and audio data in/from the disk device 13, video display on a video display unit connected to the upper control unit 9 and the like in the state where the data are continuous on the time axis. In order to perform such processes in which continuity should be maintained, by the disk device 13 performing time-division processing, the disk device 13 should store the continuous data in the memory 10 that is connected to the upper control unit 9, and perform the processes while maintaining the continuity.
Accordingly, as for the video processing in the disk device 13, there might be a case where a high processing speed is required for recording the data that are externally supplied on the disk type recording medium 1 and, simultaneously, for outputting the already-recorded data from the output unit 11 so as to reproduce the data on a monitor or the like. Further, there might also be a case where a high processing speed is not required because the data that ate recorded on the disk type recording medium 1 in the disk device 13 are only outputted from the output unit 11 so as to reproduce the data on the monitor or the like. Therefore, in the above-mentioned method wherein the user uniquely selects the processing speed, which is disclosed in Japanese Published Patent Application No. Hei. 7-334950, since the processing speed must be adjusted to the maximum speed among the processing contents so that the continuity of the continuous data is not degraded, stillness and power consumption are sacrificed in many cases.
Furthermore, since the conventional recording/playback apparatus is used as a recording unit of a computer, the upper control unit 9, in the processing mode, issues a single command, and the disk device 13 merely responds to the single command from the upper control unit 9.
This is advantageous for the upper control unit 9 which controls the whole recording/playback apparatus because the upper control unit 9 controls the disk device 13 only when required to do so and thus does not need to check the response when not required to do so, and as a result, the upper control unit 9 can efficiently control the whole apparatus. However, in the disk device 13, there arises a problem in that an appropriate operation to the processing cannot be carried out.
The present invention is made to solve the above-described problems. An object of the present invention is to provide a recording/playback apparatus for processing continuous data such as audio and video data, where the apparatus operates so as to realize device performances, such as low power consumption and stillness, that are desired by the operator without interrupting the continuous data.
According to a first aspect of the-present invention, a recording/playback apparatus comprises a disk device for recording data on a disk type recording medium; and an upper control unit for controlling processes such as input/output of data from/to the outside of the apparatus, reproduction and processing of data, as well as data processing such as reading and writing of the disk device. The upper control unit includes a composite command issuance unit which issues, to the disk device, a composite command comprising a real processing command, which is a processing command to be actually executed in the disk device, and a virtual command, which is a processing command that is expected to be issued by the upper control unit to the disk device after the disk device has processed the real processing command. The disk device comprises a lower control means for receiving the composite command from the upper control unit, and for controlling writing or reading of digital data, and a recording/playback head for performing writing or reading of digital data in/from the disk type recording medium.
Thereby, after the disk device has completed the process corresponding to the real processing command, the disk device does not go into the standby state where the disk device waits for a next command. Instead, the disk device voluntarily operates in response to the virtual command.
According to a second aspect of the present invention, in accordance with the recording/playback apparatus of the first aspect, the lower control means includes a virtual command reception means for receiving the virtual command of the composite command, and for making the disk device execute a process corresponding to the virtual command and then making the disk device standby. The process corresponding to the virtual command is a process up to a point of time when the disk device cannot continue the operation unless the virtual command is changed to the real processing command. The lower control means receives the composite command, makes the disk device carry out a process corresponding to the real processing command, makes a response to notify the upper control unit that the process corresponding to the real processing command is completed, and thereafter, the virtual command reception means performs the process corresponding to the virtual command.
Thereby, the time from when a command is issued from the upper control unit to when the process is completed can be shortened, and a risk of interrupting continuous data such as video data can be reduced.
According to a third aspect of the present invention, in accordance with the recording/playback apparatus of the first aspect, the upper control unit further comprises a judgment criteria issuance means. The judgment criteria issuance means itself creates judgment criteria which is suitable for a performance that is desired by an operator of the recording/playback apparatus, which performance is uniquely set or is selected from a plurality of prepared performances by the operator, and issues the same to the disk device. The disk device further comprises a speed switching means for switching at least either of at least two or more seek speeds which are speeds for transferring the recording/playback head, and at least two or more disk rotation speeds which are speeds for rotating the disk type recording medium. The disk device also comprises a speed selection means for selecting an optimum seek speed or disk rotation speed from the judgment criteria. The disk device receives the judgment criteria which is suitable for the performance that is desired by the operator from the judgment criteria issuance means, selects the optimum seek speed and disk rotation speed by the speed selection means, and switches the seek speed and disk rotation speed to the selected optimum speeds by the speed switching means.
Thereby, after the disk device has completed the process corresponding to the real processing command, the disk device can voluntarily operate beforehand in response to the virtual command and, furthermore, it can operate in response to both of the real processing command and the virtual command in accordance with the judgment criteria corresponding to the device performance that is desired by the operator, while switching the seek speed or the disk rotation speed, thereby performing an optimum operation in more detail.
According to a fourth aspect of the present invention, in accordance with the recording/playback apparatus of the third aspect, the judgment criteria, in accordance with the performance that is desired by the operator of the recording/playback apparatus are based on the assumption that the continuity of continuous data is maintained, include a predetermined time which restricts the frequency of switching of the disk rotation speed, and give priority to a highly expected speed in the seek speeds or disk rotation speeds.
Thereby, the upper control unit can create the judgment criteria corresponding to the device performance that is desired by the operator, and can transmit the same to the disk device.
According to a fifth aspect of the present invention, in accordance with the recording/playback apparatus of the third aspect, the upper control unit further comprises an expected time information issuance means for issuing an expected time together with the composite command to the disk device. The expected time is a time which is obtained by expecting a lapsed time from when the upper control unit issues the composite command by the composite command issuance means to when the virtual command of the composite command is issued as the real processing command.
Thereby, the disk device can operate without interrupting continuous data while switching the operation speed within the expected time, in execution of the virtual processing command and the virtual command.
According to a sixth aspect of the present invention, in accordance with the recording/playback apparatus of the third aspect, the upper control unit further comprises an expected time information issuance means for issuing an expected time and an expected command issuance interval together with the composite command to the disk device. The expected time is a time which is obtained by expecting a lapsed time from when the upper control unit issues the composite command by the composite command issuance means to when the virtual command of the composite command is issued as the real processing command. The expected command issuance interval is an interval which is obtained by expecting a command issuance interval at which a plurality of commands are issued after the composite command is issued. When the expected command issuance interval is one in which, during a set time which is set sufficiently longer than the predetermined time that is included in the judgment criteria, first expected command intervals that are approximately equal intervals are continued, and thereafter, second expected intervals that are approximately equal intervals, which are different from the first expected command intervals, are continued, the expected time information issuance means issues the first expected interval, the second expected command interval, and an expected change time at which the command interval is expected to change from the first expected command interval to the second expected command interval, together with, the composite command and the expected time, to the disk device. When the expected command issuance interval is one in which the first expected command intervals are continued during the set time, the expected time information issuance means issues the first expected command interval, the second expected command interval having the same value as the first expected command interval, and the expected change time having the same value as the set time, together with the composite command and the expected time, to the disk device.
Thereby, the disk device can perform switching of the disk rotation speed, which will take a relatively long time, as well as the seek speed, by using a long-term expectation.
According to a seventh aspect of the present invention, in accordance with the recording/playback apparatus of the sixth aspect, the disk device performs a process corresponding to the real processing command and a process corresponding to the virtual command while switching at least either of the seek speed and the disk rotation speed on the basis of the judgment criteria, processing speed information of the disk device itself, the expected time, the first expected command interval, the second expected command interval, and the expected change time.
Thereby, the disk device can perform an optimum operation for the device performance desired by the operator.
According to an eighth aspect of the present invention, in accordance with the recording/playback apparatus of the seventh aspect, the upper control unit calculates the expected time, or the first expected command interval, the second expected command interval, and the expected change time, on the basis of a processing content of continuous data controlled by the upper control unit itself, a speed at which the continuous data are processed in a memory that is connected to the upper control unit and temporarily stores the continuous data, and processing speed information of the disk device.
Thereby, continuous data to be processed, such as video data, can be processed without interrupting the data.
According to a ninth aspect of the present invention, in accordance with the recording/playback apparatus of the second aspect, the virtual command reception means performs the process corresponding to the virtual command while switching the seek speed or the disk rotation speed. The disk device issues a response to the upper control unit at the point of time when each process is completed in the process corresponding to the virtual command. Further, the upper control unit is provided with a response-to-virtual-command obtaining means for obtaining the response.
Thereby, the upper control unit can grasp the present state of the disk device, and issue a more appropriate processing command.
According to a tenth aspect of the present invention, in accordance with the recording/playback apparatus of the ninth aspect, in the process corresponding to the virtual command, when the virtual command includes reading of address and data, the disk device performs reading after seeking to the address, stores the data in the memory installed in the disk device and, thereafter, issues a response to the upper control unit, and goes into a standby state.
Thereby, when the virtual command indicating reading changes to the real processing command, the reading operation can be completed earlier, whereby data can be processed without impairing the continuity of data.
According to an eleventh aspect of the present invention, in accordance with the recording/playback apparatus of the ninth aspect, in the process corresponding to the virtual command, when the virtual command includes writing of address and data, the disk device issues a response to the upper control unit after seeking to the address, requires data to be written, stores the data to be written, which are transmitted from the upper control unit in response to the requirement, in the memory installed in the disk device, and goes into a standby state.
Thereby, when the virtual command indicates writing changes to the real processing command, the writing operation can be completed earlier, whereby data can be processed without impairing the continuity of data.
According to a twelfth aspect of the present invention, in accordance with the recording/playback apparatus of any one of the tenth or eleventh aspects, in the process corresponding to the virtual command, when data to be written are stored in the memory installed in the disk device, an approximately whole capacity of the memory is used leaving a capacity required for a minimum process such as error correction, and, when data to be written are stored, the data to be written are stored upon maintaining a minimum quantity which can be read at high speed by the disk device, in the memory, as a free capacity.
Thereby, when the virtual command is not changed to the real processing command as expected, an advance process corresponding to the virtual command can be executed without losing data for writing, which data are required for recording.
According to a thirteenth aspect of the present invention, in accordance with the recording/playback apparatus of the third aspect, the disk device stores an operation speed of the disk device itself, an operation switching speed, information concerning power consumption, and the like in the disk type recording medium or in an nonvolatile memory which is installed in the disk device, in a predetermined format; and the upper control unit obtains the information as required at start-up or the like of the recording/playback apparatus, and creates the appropriate judgment criteria, thereby controlling the disk device.
Thereby, even when the disk device is exchanged due to failure or the like, the upper control unit can obtain information required when creating the judgment criteria, and can update the judgment criteria.